Percona Server for MySQL 5.6.26-74.0

Percona is glad to announce the release of Percona Server for MySQL 5.6.26-74.0 on September 15th, 2015 (Downloads are available here and from the Percona Software Repositories).

Based on MySQL 5.6.26, including all the bug fixes in it, Percona Server for MySQL 5.6.26-74.0 is the current GA release in the Percona Server for MySQL 5.6 series. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.6.26-74.0 milestone at Launchpad.

TokuDB storage engine source has been merged into the Percona Server for MySQL code. TokuDB storage engine tokudb_version variable now has the same value as the Percona Server for MySQL version variable version.

TokuDB Hot Backup has been renamed to Percona TokuBackup and it is now open source. Source code has been integrated into Percona Server for MySQL code as a git submodule. TokuDB Hot Backup plugin source has been merged into Percona Server for MySQL code.

Tokutek Fractal Tree has been renamed to Percona FT and its source code has been integrated into Percona Server for MySQL code as a git submodule.

TokuDBtests for Percona Server for MySQL 5.6 have been merged into Percona Server for MySQL 5.6 code.

Percona Server for MySQL now supports changing the server_id variable per session, by implementing the new pseudo_server_id variable. This feature is also fixing upstream bug #35125.

Percona Server for MySQL has temporarily disabled savepoints in triggers and stored functions. The reason is that even having fixed bug #1438990 and bug #1464468 we have found more cases where savepoints in triggers break binary logging and replication, resulting in server crashes and broken slaves. This feature will be disabled until the above issues are properly resolved.

LOCKTABLESFORBACKUP now flushes the current binary log coordinates to InnoDB. Thus, under active LOCKTABLESFORBACKUP, the binary log coordinates in InnoDB are consistent with its redo log and any non-transactional updates (as the latter are blocked by LOCKBINLOGFORBACKUP). It is planned that this change will enable Percona XtraBackup to avoid issuing the more invasive LOCKBINLOGFORBACKUP command under some circumstances.

innodb_stress has been added to the list of default MTR suites. For most supported systems satisfying the newly added dependencies is straightforward, but on CentOS 5, the default Python is too old. Thus python26 and python26-mysqldb packages should be installed there and python26 should be made the default python for the testsuite environment.

Percona Server for MySQL has implemented new tokudb_compress_buffers_before_eviction option in TokuDB which allows the evictor to compress unused internal node partitions in order to reduce memory requirements as a first step of partial eviction before fully evicting the partition and eventually the entire node.

When variable innodb_corrupt_table_action is set to Warn/Salvage then server could crash on updating table statistics during query execution on affected tables. Bug fixed #1426610.

A sequence of failing TRUNCATETABLE, then insert to that table, and CHECKTABLE would crash the server. Bug fixed #1433197.

When InnoDB change buffering was enabled and used, executing a FLUSHTABLE...FOREXPORT would cause a server hang and SHOWPROCESSLIST would show that table in a SystemLock state. Bug fixed #1454441 (upstream #77011).

FLUSHINDEX_STATISTICS / FLUSHCHANGED_PAGE_BITMAPS and FLUSHUSER_STATISTICS / RESETCHANGE_PAGE_BITMAPS pairs of commands were inadvertently joined, i.e. issuing either command had the effect of both. The first pair, besides flushing both index statistics and changed page bitmaps, had the effect of FLUSHINDEX_STATISTICS requiring SUPER instead of RELOAD privilege. The second pair resulted in FLUSHUSER_STATISTICS destroying changed page bitmaps. Bug fixed #1472251.

Enabling super_read_only together with read_only in my.cnf would result in server crashing on startup. The workaround is to enable super_read_only dynamically on a running server.Bug fixed #1389935 ( the fix was ported from Facebook patch #14d5d9).

If a new connection thread was created while a SHOWPROCESSLIST command or a INFORMATION_SCHEMA.PROCESSLIST query was in progress, it could have a negative TIME_MS value returned in the PROCESSLIST output. Bug fixed #1379582.

With Support for Fake Changes enabled, a write to an InnoDB table that would cause B-tree reorganization could lead to server assertion with unknownerrorcode1000. Bug fixed #1410410.